Lolita Meetup Must Haves?

Evening, ladies and gents.

This topic is pretty simple, but it's something I've been curious about. I've been interested in hosting meetups for a while, but I'm not sure where to begin! How organized should it be? Is there such a thing as too organized? What are good places to go? What makes a meetup a good meetup or a great one? What about a bad one?

I'd love to hear your tips, tricks, and stories regarding meetups you've been in or hosted in the past! What do you think hosts should take into consideration when planning their meetups?

(This is my first time posting so I apologize if I tagged it wrong or this is a repetitive topic!)